A ferrocene-containing side-chain liquid-crystalline polymethacrylate was oxidized with iodine into the corresponding ferrocenium polymeric species. The reduced polymer showed enantiotropic smectic C and smectic A phases. The oxidized polymer exhibited an enantiotropic nematic phase. The results described in this report confirm that ferrocene is a valuable redox-active unit for the design of switchable liquid-crystalline polymers.